There's more to mobile apps than ringtones, text messages and casual games: "Intended to promote a UK TV show called 'Derek Acorah's Ghost Towns,' the detector - co-developed with mobile specialist Future Platforms - purportedly uses existing mobile phone technology and 'current parapsychological theory' to 'detect subtle electrical changes around the user that some experts say are associated with paranormal activity,' says Wiretown co-founder Tim Usborne."

I really enjoyed "My so-called second life" yesterday; it had a good line-up of speakers and some really thought-provoking stuff.

I'll declare a certain bias: Esther is a friend and former denizen of Rosehill, but I found her (and Justin's) talk fascinating. I've not used WoW or Second Life myself, and having seen a few folks having trouble extracting themselves I'm reluctant to give them the time they'd need, but they look worth investigating. I got to bond with Helen on the this-stuff-makes-me-feel-old front :)

In particular the comparison of WoW and 2L as games vs social spaces was interesting. Outside I quizzed E&J about ways that MMORPG or similar might be made "casual" and moved to mobile. It was only on the way home that I realised one model for taking these games onto phones might be the one which Twitchr followed - a game which requires small bursts of attention, but sits at the back of your mind throughout the day. Ah well.

The IBM guy talking about use of virtual spaces? I was a bit sceptical about this, but like I say, I'm behind the curve in this area. I loved the use of 3D to present Wimbledon (complete with ball trajectories etc.) but as a general social space for businesses I'm more sceptical: I'd expect to see the corporate world use more specialist tools.

Thanks to Mike for arranging the day, and all the speakers!

SavaJe falls quiet: "SavaJe, pioneer of the concept of a Java-based mobile phone, appears to have gone into hibernation, leaving a few million lines of code and a bunch of arguing venture capitalists."

A shame. They'd been offering operators a chance to own the handset UI for a while now, and though they hadn't launched any devices they had a decent product. I remember getting a demo at 3GSM last year, they'd gotten our Sudoku game running...

7 reasons why Threadless rules: "Real, profitable, human, funny, quality, charitable, and independent."

I was chatting to a guy from a Big Operator yesterday, and during a chat about SMS and instant messaging he mentioned something I'd never considered: the impact of presence on radio networks.

Consider a typical user who has 10 calls a day and receives 10 text messages; this activity results in his handset being contacted on the local network 20 times in a day (my operator chum referred to these contacts as "pages"). Now consider what happens if this user has 10 buddies in an IM list and is alerted whenever they drop offline or come online: suddenly the number of pages rises to hundreds per day.

This rise impacts both battery life of the device itself, and traffic on the radio network. The operator in this case did a couple of studies and experiments which confirmed this scenario, and in fact painted a gloomier picture around networks collapsing once IM-enabled users hit a certain (low) threshold.

This says to me that IM in its current form won't threaten SMS revenues for a good few years: a bit like Wi-Fi, whilst we can see it starting to creep in at the edges, it's not ready for mass adoption and won't scale up in the way that SMS on current GSM/3G networks does.

What are possible solutions? Limit the number of presence-aware contacts in individual address books, to reduce the network effects of all those presence updates; allocate a new radio channel for presence information (but that'll take 5-10 years to sort out); and IM vendors optimising their products to be sensitive to the needs of mobile networks could help a little - in the short term. And of course, if unchecked IM threatens operators abilities to offer their core services - voice and text - over their networks, then we can expect to see them clamp down on it (presumably taking a fair amount of flak from the lets-replace-operators-with-wifi brigade).